Endoscopic instrument

Abstract

Endoscopic instrument with an elongated shaft (1) and a distal instrument head (4) which is controllable from the proximal instrument end, with a joint (6) in the shaft (1) or between the distal shaft end and the instrument head (4), with gear means for pivoting a distal joint part (9) with respect to a proximal joint part (8), and with gear means for transmitting at least one control function from the proximal instrument end to the instrument head (4), characterized in that - that the transmission means comprise a planetary gear, the central axis (7) of which coincides with the joint axis (7), wherein the planetary gear comprises a sun gear (S), a ring gear (H1) and planetary gears (P1) rotatably mounted therebetween in a planet carrier (T1), which planetary gears couple the sun gear (S) and the ring gear (H1) to one another in terms of movement, wherein the planet carrier (T1) is connected in a rotationally fixed manner to one joint part (8) and the ring gear (H1) is connected in a rotationally fixed manner to the other joint part (9), - that the transmission means comprises a further planetary gear for transmitting a further control function with a further ring gear (H2, H3) and a further planet carrier (T2, T3) with planet gears (P2, P3) rotatably mounted therein, which are coupled in motion by a sun gear (S), and - that the planetary gears have a common sun gear (S).

Description

[0001] The invention relates to an endoscopic instrument having the features specified in the preamble of claim 1.

[0002] Endoscopic instruments of this type are either provided with a handle on the proximal side, via which various movement functions can be controlled, or, as may be the case with more complex instruments, with a proximal connection device with which the instrument can be connected to an arm of a robotic system, by means of which the individual functions can be controlled by an electric motor. The robotic system itself is then controlled in a suitable manner, as is part of the state of the art. Such an instrument is known, for example, from US 7,524,320 B2. This instrument has an elongated shaft, at the distal end of which an instrument head is arranged, which can be controlled from the proximal end of the instrument. For this purpose, a connection device is provided on the proximal side, with which the instrument can be connected to a robotic arm, via which all functions can then be controlled.

[0003] In order to increase the movement possibilities of the distal end of the instrument, on which, for example, a tool in the form of scissors, forceps, a needle holder or the like is arranged, it is state of the art to provide a joint in the region of the distal shaft end or between the distal shaft end and the instrument head in order to be able to deflect the instrument head relative to the shaft axis. A problem with such joints is always the implementation of the control means with which the instrument parts located behind the distal side are actuated, for example for opening and closing forceps on the instrument head or for rotating the instrument head. For this purpose, it is usually necessary to provide gear means for transmitting the control functions from the proximal end of the instrument to the instrument head. In the instrument known from US 7 524 320 B2, this is achieved by means of cables that are deflected via corresponding rollers in the region of the joint.

[0004] A disadvantage of the gearing described therein is that it is not possible to pivot the instrument head without affecting the other gearing. This is still tolerable in robotic applications, since the corresponding compensation can be achieved automatically by an electric motor, so that this mutual influence of the control means is not noticeable to the user. However, this requires increased control engineering effort, which is fundamentally disadvantageous. However, such mutual influence of the control means is problematic if the instrument is to be operated by a proximal handle.

[0005] According to US 2009 / 0 182 193 A1, it is state of the art to provide a planetary gear whose central axis coincides with the joint axis between the distal shaft end and the instrument head.

[0006] From US 2010 / 0 240 954 A1, a flexible endoscope is part of the state of the art, in which a distal endoscope section is arranged so as to be rotatable about the shaft axis or parallel to it relative to the remaining flexible shaft by means of a gear, for example a planetary gear.

[0007] Against this background, the invention is based on the object of improving a generic endoscopic instrument in which it is possible to generate a pivoting movement between the instrument shaft and the instrument head without the control means implemented in this area being influenced thereby.

[0008] This object is achieved according to the invention by an endoscopic instrument having the features specified in claim 1.

[0009] The endoscopic instrument according to the invention comprises an elongated shaft and a distal instrument head that can be controlled from the proximal end of the instrument. It comprises a joint in the shaft or between the distal end of the shaft and the instrument head, as well as means for pivoting a distal joint part relative to a proximal joint part. Furthermore, gear means are provided for transmitting at least one control function from the proximal end of the instrument to the instrument head. The gear means are formed by at least one epicyclic gear, the central axis of which coincides with the joint axis.

[0010] This enables a pivoting movement of the joint through purely mechanical means, namely an epicyclic gear. With a suitably designed gear, the joint can be pivoted without the control elements, typically tension wires or tie rods, moving relative to each other. However, if desired, a targeted movement can also be generated, depending on the gear ratio selected in the epicyclic gear. Furthermore, the epicyclic gear enables a gear ratio of the control elements, meaning that, depending on the gear ratio, the force can be specifically increased or decreased, or the stroke can be increased or decreased. Such an epicyclic gear, whose central axis coincides with the joint axis, can be designed compactly and thus saves space.

[0011] According to the invention, a planetary gear in the form of a gear train is used as the epicyclic gear, which has at least one sun gear and at least one ring gear. Planetary gears are provided between the sun gear and the ring gear, which planetary gears are rotatably mounted in a planetary carrier and which couple the sun gear to the ring gear. The planetary carrier is rotationally fixedly connected to one joint part, and the ring gear is rotationally fixedly connected to the other joint part. These connections create the control functions, which ensure that when the joint is pivoted, the other control means in this area are adjusted in such a way that the pivoting has no influence on the handle side or the distal instrument head or the tool located there.

[0012] To transmit a further control function, the transmission means comprise a further planetary gear with a further ring gear and a further planet carrier with planet gears rotatably mounted therein, wherein the coupling with respect to the pivoting movement is effected via a common sun gear which couples the ring gears and the planet gears in the planet carriers to one another in terms of movement.

[0013] The arrangement described above is particularly advantageous because the connection of the control means is located at a significant radial distance from the axis of rotation of the joint or the central axis of the transmission. However, a kinematic reversal is also possible in principle.

[0014] In this way, practically any control function can be transmitted by providing an additional ring gear and an additional planet carrier with planet gears rotatably mounted therein for each control function, with the movement coupling taking place via the central sun gear.

[0015] The sun gear can be provided with continuous spur gearing, but a stepped design is also conceivable in order to individually adjust the gear ratios between the individual control means.

[0016] It is particularly advantageous if the control function is carried out via tension and / or compression transmitters guided in the shaft, for example, rods or wires, each of which is attached to a ring gear or a planetary carrier at a distance from the joint's axis of rotation. Such tension or compression transmitters are state-of-the-art and are also used in state-of-the-art instruments to transmit the control functions.

[0017] It is particularly advantageous if each control function is transmitted via a pair of tension / compression rods guided in the shaft, which are connected to two pivot points on the ring gear or planetary carrier, offset by approximately 180°. Such a "dual" control enables a virtually backlash-free and high-force-transmitting control function, which, due to its symmetrical arrangement to the joint axis, is largely independent of the direction of movement. Thus, for example, it can be used in a pair of pliers with the same force for opening and closing.In this case, it is particularly advantageous for the present application, in which a joint is provided which pivots a distal part of the instrument relative to the shaft axis, if the articulation points on the ring gear and on the planet carrier have the same radial distance from the axis of rotation or, if necessary, a deliberately different distance in order to achieve a suitable force-displacement transmission in conjunction with the transmission ratio of the gear. The articulation points are advantageously also articulated in order to ensure movement with as little friction as possible. In particular if the instrument is to be controlled manually, it is advantageous to design the transmission ratio of the planetary gear in such a way that a pivoting movement of the joint is independent of the transmission of the control functions. This is a particular advantage achieved by the epicyclic gear. It goes without saying that, for example, when the instrument is used robotically, i.e.i.e. if such a transmission of the control function independent of the pivoting movement may be unnecessary, the epicyclic gear according to the invention can also be used specifically for other purposes, for example if special transmission ratios are to be realized in the control functions.

[0018] The movement coupling within the transmission between the pivoting movement of the joint and the corresponding compensating movements of the control elements is achieved by the central sun gear. In its simplest form, this is designed with uniform spur gearing throughout, but shoulders with different tooth pitches can also be provided to achieve specific gear ratios. The design possibilities here are virtually limitless.

[0019] The invention is explained in more detail below using an exemplary embodiment illustrated in the drawing. In the drawings: Fig. 1 shows a highly simplified perspective view of an endoscopic instrument according to the invention, Fig. 2 in perspective view the joint area in non-angled position, Fig. 3 the joint area in an angled position in the illustration according to Fig. 2, Fig. 4 the gear structure in the joint area in illustration according to Fig. 3, Fig. 5 Joint and gear in exploded view and Fig. 6 Joint and gear in assembled form in perspective view.

[0020] The endoscopic instrument is in its basic structure in Fig. 1. It has an elongated shaft 1, which on the proximal side has an operating and control part 2, which is shown here only as a "black box". This can be an operating and control part 2, as is known, for example, from US 7,524,320 B2, or a manually operated operating and control part 2, as is state of the art for endoscopic instruments in numerous design variants. The shaft 1 has a distal end region 3, to the end of which an instrument head 4 is attached, which is shown here as a pair of forceps by way of example. This instrument head 4 represents any tool that can be operated from the proximal operating and control part 2.

[0021] The endoscopic instrument has a longitudinal axis 5, which is determined by the longitudinal axis of the shaft 1. The instrument head 4 can be pivoted out of this longitudinal axis 5; for this purpose, a joint 6 is provided in the distal end region 3, the joint axis 7 of which intersects the longitudinal axis 5 perpendicularly. The structure of this joint is shown in the Fig. 2 - 6 are shown in detail.

[0022] The joint 6 serves to angle the instrument head 4 relative to the shaft 1 and is controllable from the operating and control part 2 with regard to its pivoting position. It consists of a proximal joint part 8, which continues the outer contour of the shaft 1 and is firmly connected to it, as well as a distal joint part 9, which in the straight position also continues the outer contour of the shaft and is firmly connected to the distal shaft end and the instrument head 4 attached to it. The joint parts 8 and 9 are each cut out of their fully cylindrical material towards the axis of rotation 7 of the joint to form two tongues 10 and 11, respectively, offset by 180° from one another, wherein the tongues 10 of the proximal joint part 8 continue the cylindrical outer contour, whereas the tongues 11 of the distal joint part 9 are arranged offset inwards so that they can be incorporated between the tongues 10, as can be seen in particular from the Fig. 2, Fig. 3 and Fig.6. They each have a bore 12 which serves to accommodate a joint axis.

[0023] In the joint parts 8 and 9, with respect to the straight position of the joint 6, elongated holes 13 are provided parallel to the longitudinal axis 5, which serve to guide pull / push rods 14 which serve to control the angulation of the joint and to control the instrument head 4. To control the angulation of the joint 6, i.e. of the distal joint part 9 relative to the proximal joint part 8 and the shaft 1, two pull / push rods 14 are provided which are offset from one another by 180° with respect to the axis of rotation 7 of the joint 6, which are guided only through the proximal joint part 8 and end within the joint. The pull / push rods 14 are articulated at their distal ends to a ring gear H1, which is connected in a rotationally fixed manner to the distal joint part 9 and has an internal toothing which engages with planet gears P1, which are rotatably mounted in an annular planet carrier T1 and mesh centrally with a sun gear S.The planet carrier T1 is firmly connected to the proximal joint part 8, forms a bearing surface on its outer circumference, on which a tongue 11 with its bore 12 runs and thus forms the pivot bearing of the joint 6.

[0024] The planet carrier T1 has three axle bolts 15 arranged parallel to the joint axis 7 on the flat side facing the inside of the joint, on which the planet gears P1 are rotatably mounted. Since the planet carrier T1 is firmly connected to the proximal joint part 8 and the ring gear H1 is firmly connected to the distal joint part 9, the pivoting movement of the distal joint part 9 with respect to the proximal joint part 8 can be controlled by means of the pull / push rods 14. Since the planet gears P1 roll on the internal teeth of the ring gear H1 during a pivoting movement of these components relative to one another, a corresponding rotational movement of the sun gear S occurs, which meshes internally with the planet gears P1.

[0025] The sun gear S controls further gear stages of the planetary gear thus formed, which are intended for the transmission of further control functions.

[0026] In the illustrated embodiment, two further gear stages are provided, namely for transmitting movements which are generated via pull / push rods 16 which are also arranged offset by 180° relative to the shaft axis 5 and which are moved from the proximal operating and control part 2 in order to provide a corresponding control function on the instrument head 4, for example the opening and closing of a forceps.These pull / push rods 16 are articulated on the outer circumference of a planet carrier T2 offset by 180° to one another, which is ring-shaped and also has laterally projecting axle bolts 20 parallel to the joint axis 7, on which planet gears P2 are rotatably mounted, which on the one hand mesh with the central sun gear S and on the other hand with an internal toothing of a ring gear H2, on the outer circumference of which two pull / push rods 17 are articulated, also offset by 180° to one another, which transmit the movements of the pull / push rods 16 further distally.

[0027] Parallel to the pull / push rods 14 and 16, pull / push rods 18 are also guided in the shaft 1, the ends of which are articulated on the outer circumference of a planet carrier T3 offset by 180° to one another, which also has laterally projecting axle bolts 21 parallel to the joint axis 7, on which planet gears P3 are rotatably mounted, which mesh on the one hand with the central sun gear S and on the other hand with the internal toothing of a ring gear H3, on the outer circumference of which the distal ends of pull / push rods 19 are each articulated offset by 180°, which transmit the movements of the pull / push rods 18 distally, i.e. towards the instrument head, and are used, for example, to rotate the head 4 about the shaft axis.

[0028] The transmission kinematics here consists of planetary gear stages connected in series. In the illustrated embodiment, the first gear stage consists of the ring gear H1, the planet carrier T1, the planet gears P1, and the sun gear S. The number of teeth of the ring gear H1 is Z. H1 and the number of teeth of the sun gear S is z S. The planet carrier T1 is concentrically connected to the proximal joint part 8 and is provided on the outside with a bearing surface for the distal joint part 9. The ring gear H1 is firmly connected to the distal joint part 9. In addition, the ring gear H1 has joints on its outer circumference to which the pull / push rods 14 are articulated. If the pull / push rods 14 are moved, the movement is transferred to the ring gear H1 and, via the planet gears P1, to the planet carrier T1, which is firmly connected to the distal joint part 9. The distal joint part 9 is then pivoted about the joint axis 7. Since the planet carrier T1 is firmly connected to the proximal joint part 8, the rotation of the ring gear H1 simultaneously causes a rotation of the sun gear S with the transmission ratio i1 = - z S / z H1If the pull / push rods 14 are moved, the pull / push rods 16 and 18 and thus the planet carriers T2 and T3 are stationary. Since the common sun gear S rotates, this rotational movement is transmitted with the ratio i2 = -z H2 / z S transferred to the ring gear H2, where z H2 the number of teeth of the ring gear H2. If i1 = i2, or with a common sun gear z H1 = z H2 , the motion transmission from H1 to H2 for the total transmission i ges= i1 × i2 = 1. The ring gear H2 thus rotates relative to the proximal joint part 8 by the same amount as the ring gear H1 or the distal joint part 9. Thus, the relative positions of the pull / push rods 17 and 19 to the distal joint part 9 are maintained, i.e., the pivoting movement of the joint 6 has no influence on the motion transmission. In the illustrated embodiment, the current pivoting position of the pliers and the rotational position of the head are maintained regardless of the pivoting position of the joint.

[0029] The second and third stages of the planetary gear are provided to transmit the movement of the pull / push rods 16 and 18 to the pull / push rods 17 and 19. The movement of the pull / push rods 16 is translated into a rotational movement of the planet carrier T2, whose rotation, with the sun gear S stationary, causes a rotational movement of the ring gear H2 with the ratio i2A=11+zSzH. This inevitably results in a gear ratio. With a practical tooth ratio of, for example, z S = ½ z H This results in a gear ratio i2A=23. At zS=13zH z S is i2A=34. Thus, a slight translation of the rotational movement of the planet carrier T2 to the ring gear H2 takes place. The above-described ratio applies accordingly to the transmission of the movements of the pull / push rods 18 and 19, or to the ring gear H3 and the planet carrier T3.

[0030] If a reduction in motion is desired, the above-described design can be achieved by a different combination of sun gear, planet carrier, and ring gear with the joint parts 8 and 9. For example, the proximal joint part 8 can be firmly connected to the ring gear H1, and the planet carrier T1 can be firmly connected to the distal joint part 9. The pull / push rods 16 are then connected to the ring gear H2, and the output-side pull / push rods 17 are connected to the planet carrier T2. Furthermore, the number of teeth of the gears can be varied according to the desired transmission ratios.

[0031] Instead of push / pull rods, cable drives can also be used, which enclose the corresponding peripheral surfaces or are attached to them. By varying the ratios of the planetary gear, effects can be achieved that, for example, significantly increase the gripper force or the travel stroke. In this way, the gear can be adapted to the specific application requirements. List of reference symbols 1 shaft 2 Operating and control unit 3 distal end area 4 Instrument head 5 Longitudinal axis 6 joint 7 Joint axis 8 proximal joint part 9 distal joint part 10 tongues of 8 11 tongues of 9 12 Hole in the tongues 13 long holes 14 tension / compression rods 15 axle bolts from P1 16 pull / push rods 17 tension / compression rods 18 pull / push rods 19 pull / push rods 20 axle bolts from P2 21 axle bolts from P3 T1 - T3 planet carrier P1 - P3 planetary gears H1 - H3 ring gears S sun gear

Claims

[1] Endoscopic instrument with an elongated shaft (1) and a distal instrument head (4) which is controllable from the proximal instrument end, with a joint (6) in the shaft (1) or between the distal shaft end and the instrument head (4), with gear means for pivoting a distal joint part (9) with respect to a proximal joint part (8), and with gear means for transmitting at least one control function from the proximal instrument end to the instrument head (4), characterized by , - that the transmission means comprise a planetary gear, the central axis (7) of which coincides with the joint axis (7), wherein the planetary gear comprises a sun gear (S), a ring gear (H1) and planetary gears (P1) rotatably mounted therebetween in a planet carrier (T1), which planetary gears couple the sun gear (S) and the ring gear (H1) to one another in terms of movement, wherein the planet carrier (T1) is connected in a rotationally fixed manner to one joint part (8) and the ring gear (H1) is connected in a rotationally fixed manner to the other joint part (9), - that the transmission means comprises a further planetary gear for transmitting a further control function with a further ring gear (H2, H3) and a further planet carrier (T2, T3) with planet gears (P2, P3) rotatably mounted therein, which are coupled in motion by a sun gear (S), and - that the planetary gears have a common sun gear (S). [2] Instrument according to one of the preceding claims, characterized bythat, in order to transmit further control functions, further ring gears (H) and further planet carriers (T) with planet gears (P) rotatably mounted therein are provided, which are motion-coupled via the common sun gear (S). [3] Instrument according to one of the preceding claims, characterized by that a control function is carried out via tension and / or pressure transmitters (14; 16 - 19) guided in the shaft (1), which are each fixed to a ring gear (H) or a planet carrier (T) at a distance from the axis of rotation (7) of the joint (6). [4] Instrument according to one of the preceding claims, characterized by that a control function is transmitted via a pair of tension / compression rods (16 - 18) guided in the shaft, which are articulated at two articulation points on the ring gear (H) or on the planet carrier (T) arranged offset by 180°. [5] Instrument according to one of the preceding claims, characterized bythat the articulation points on the ring gear (H) and on the planet carrier (T) have the same radial distance from the axis of rotation (7). [6] Instrument according to one of the preceding claims, characterized by that the transmission ratio of the planetary gear is designed so that a pivoting movement of the joint (6) is independent of the transmission of the control functions. [7] Instrument according to one of the preceding claims, characterized by that the sun gear (S) is offset.

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